JP3952485B2

JP3952485B2 - Bath water heater

Info

Publication number: JP3952485B2
Application number: JP02791299A
Authority: JP
Inventors: 良彦田中
Original assignee: Noritz Corp
Current assignee: Noritz Corp
Priority date: 1999-02-04
Filing date: 1999-02-04
Publication date: 2007-08-01
Anticipated expiration: 2019-02-04
Also published as: JP2000227250A

Description

【０００１】
【発明が属する技術分野】
本発明は風呂給湯装置に関する。特に、浴槽内の湯の追焚き用の伝熱管を給湯用の熱交換器の水壁内に納めた１缶２水路貯湯方式の風呂給湯装置に関する。
【０００２】
【従来の技術】
風呂給湯装置で貯湯部を有する、いわゆる貯湯式風呂給湯装置では、１缶２水路（１バーナ）方式のものが主流である。この方式では、浴槽の追焚き回路の熱交換部、即ち伝熱管を給湯用の熱交換器の水壁内に収め、当該水壁内温水温度を検知しながら１箇所のバーナで給湯用熱交換器を加熱することで当該給湯用熱交換器の水壁内の水を加熱して設定温度の温水とするとともに、水壁内の追焚き回路の伝熱管内を流れる浴槽循環水を間接的に加熱するようにしたものである。又、このような貯湯式のものではバーナに燃焼能力（燃焼熱量）固定で断続燃焼制御のものを用いるのが一般的である。
【０００３】
また一方、浴槽内の湯の残量を検出する方法としては、熱量演算方式と呼ばれるものがある。この方法は、2缶2水路（2バーナ）方式のものに多く採用されるものであり、浴槽内にバスアダプタレベル以上の残水が存在する場合の残水量検出方法であって、浴槽内の湯を追焚き回路内に循環させることにより浴槽内の湯の加熱前温度を検出しておき、次いで一定時間追焚き回路で浴槽内の湯を加熱し、追焚き終了後に再び浴槽内の湯の焚き上がり温度を検出する。追焚き回路の燃焼能力（燃焼熱量）は予め分かっているので、焚き上がり温度と加熱前温度の温度差と燃焼時間とから浴槽内の残水量を熱力学的に計算することができる。
【０００４】
しかしながら、１缶２水路方式の貯湯式風呂給湯装置では、１箇所のバーナによって給湯用熱交換器の水壁内の水を加熱し、間接的に当該水壁内の追焚き用伝熱管内を流れる浴槽循環湯を加熱しているので、熱量演算の為の追焚き中に給湯用熱交換器の水壁内の湯を、給湯栓を開いて出湯すると、バーナからの供給熱量の一部がそちらに奪われ、浴槽循環湯への供給熱量、即ち風呂能力（以下、風呂能力と記す。）が減り、バーナの燃焼能力（燃焼熱量）が固定されていても、焚き上がり温度と加熱前温度の温度差と燃焼時間とから浴槽内の残水量を熱力学的に計算することができない。
この給湯側に奪われた熱量、即ち給湯能力（以下、給湯能力と記す。）が算出できれば、風呂能力が算出できるが、貯湯式の場合、一般的に給湯回路に水量センサは設けられておらず、この計算もできない。
【０００５】
また、１缶２水路方式の貯湯式風呂給湯装置では、給湯使用しなくても、浴槽内の湯の温度、つまり追焚き用の伝熱管に流入する湯の温度が変化すると、それに伴い、給湯用熱交換器の水壁内の温水を一定温度に保持するのに必要な熱量も変化し、又、熱交換効率も変化する為、バーナの燃焼能力（燃焼熱量）も大きく変化する。（例えば、湯温４０℃では、１０℃の場合と比較して５０％以上燃焼能力が低下する。）
ここでは給湯使用しない場合としたので、バーナの燃焼能力（燃焼熱量）は、即ち風呂能力を指す。
【０００６】
また、燃焼能力（燃焼熱量）可変のバーナを連続燃焼させる場合には、一定時間の燃料の消費量を知ることにより与えた熱量を容易に算出できるが、バーナに燃焼能力（燃焼熱量）固定で断続燃焼制御のものを用いる場合には、一定時間に与えた熱量を精度良く検知しようとすると、当該一定時間を長くとる必要があり、現実的ではない。
故に、このことによっても焚き上がり温度と加熱前温度の温度差と燃焼時間とから浴槽内の残水量を熱力学的に計算することができない。
よって浴槽内の残水量を測定する為に風呂アダプタに圧力センサを配し、風呂アダプタより上の水位について当該圧力センサの出力により、浴槽内の残水量を測定する方法が採られている。
【０００７】
しかしながら風呂アダプタに圧力センサを配する方式では、施工現場で風呂アダプタから圧力センサの信号線を取り出し、壁内配線する必要があり、初期施工時、及び、圧力センサ故障に伴う、交換又は修理工事の際に多大な工数を必要としていた。
【０００８】
【発明が解決しようとする課題】
本発明は上述の技術的問題点を解決するためになされたものであり、その目的とするところは熱量演算方式によって残水量を演算する機能を備えた１缶２水路貯湯方式の風呂給湯装置において、熱量演算により正確に残水量を演算できるようにすることにある。
【０００９】
【課題を解決するための手段】
請求項１に記載の風呂給湯装置は、１箇所のバーナによって給湯用の熱交換器を直接加熱し、又、当該熱交換器の水壁内に配された追焚き用の伝熱管を当該水壁内の温水で間接的に加熱する風呂給湯装置において、浴槽内の湯温と当該水壁内温水温度を検出するための温度検知手段を備え、当該温度検知手段によって検知された浴槽内の湯温と当該水壁内温水温度に基づき、熱量演算方式による残水量演算に用いる風呂能力を求めるようにしたことを特徴としている。
【００１０】
ここで、熱量演算方式の残水量演算とは、浴槽内に残っている湯を所定時間加熱し、加熱開始前の湯温と加熱終了後の湯温の温度差及びその間に浴槽内の湯に与えられた熱量から残水量を求める方法である。また、浴槽内の湯温によって熱量演算方式による残水量演算に用いる燃焼能力、すなわち風呂能力を決めるためには、予め浴槽内湯温と給湯熱交換器の水壁内温水温度と風呂能力との関係を記憶装置などに記憶させておく。
ここで浴槽内湯温は循環回路の戻り湯温を循環回路途中に配した温度センサで検知しても良いし、浴槽の風呂アダプタに温度センサを配して直接検知しても良く、又、その他の方法でも直接、或いは間接的に浴槽内湯温を検知できる方法で有れば構わない。以下の説明ではこの浴槽内湯温を風呂温度と記す。
又、給湯熱交換器の水壁内温水温度も、その検知位置により検知値は異なるが、当該水壁内温水温度を直接、或いは間接的に検知できる位置であれば良い。以下の説明ではこの水壁内温水温度を缶体温度と記す。
【００１１】
本発明の風呂給湯装置にあっては、風呂温度、及び、缶体温度に応じて残水量演算に用いる風呂能力を求めるようにしているので、風呂温度、及び、缶体温度に応じて補正された風呂能力の値を用いることができ、いわゆる１缶２水路貯湯方式の風呂給湯装置で、バーナに燃焼能力（燃焼熱量）固定で断続燃焼制御のものを用いる場合においても熱量演算によって浴槽内の残水量を正確に求めることができる。
【００１２】
【発明の実施の形態】
図１は本発明の一実施形態による１缶２水路貯湯方式の風呂給湯装置１を示す概略構成図である。この風呂給湯装置１はオイルを燃料とするオイル式であって、給湯用熱交換器２の下部にオイルを燃焼させるためのバーナ３が設けられており、オイルポンプ５によりオイル供給管４からオイルが供給され、缶体サーミスタ９で検知された缶体温度を設定温度に保持すべく燃焼能力（燃焼熱量）固定で断続燃焼制御される。
また、バーナ３の上部には燃焼用の空気を強制的に送り込むための送風機６が設けられており、送風機６から強制送風された空気や排気ガス等は排気筒７から外部へ排出される。また、給湯用熱交換器２の水壁内には浴槽２８のバスアダプタ２９に接続された追焚き回路４０の追焚き用熱交換部である伝熱管８が配設されている。
【００１３】
給湯路３０は、給湯用熱交換器２の入水側に接続された入水路１０と出湯側に接続された出湯路１１とからなり、入水路１０には逆止弁１２、減安弁１３が設けられている。しかして、出湯路１１の管端に設けられた給湯栓１６が開かれると、給湯路３０を流れる水はバーナ３で熱せられている給湯用熱交換器２によって加熱され、設定温度の湯として給湯栓１６から出湯される。
【００１４】
追焚き回路４０は追焚き用熱交換部である伝熱管８、伝熱管８に接続された戻り管１９及び往き管２３からなり、戻り管１９には循環ポンプ２０、浴槽湯温検知センサ２１、水流スイッチ２２が設けられている。しかして、浴槽２８内の湯を追焚きする場合には、循環ポンプ２０を運転して循環判定によりバスアダプタレベル以上の湯があることを確認した後、バーナ３で熱せられている給湯用熱交換器２の水壁内に配された伝熱管８で追焚き回路４０を循環する湯を加熱し、浴槽湯温検知センサ２１で検出している浴槽２８内の湯の温度が設定温度に達すると循環ポンプ２０の運転を停止する。
【００１５】
また、出湯路１１の管端部分から分岐した湯落とし込み路４１は、入水路１０とバイパス流量調整弁１８を備えたバイパス路１７とオリフィス４６を介して接続されるとともに、落とし込み開閉弁２４及び、注湯水量センサ２５、逆止弁４２、４３を介して追焚き回路４０の往き管２３途中に接続されており、往き管２３と戻り管１９との間には逆止弁４４を備えたバイパス流路２６が設けられている。しかして、浴槽２８内に湯を落とし込んで浴槽２８内に湯張りする場合には、落とし込み開閉弁２４を開き、給湯路３０の給湯用熱交換器２で加熱され、出湯路１１から流出した湯をオリフィス４６で流量を規制し、追焚き回路４０の往き管２３に配した注水サーミスタ２７で温度を検知しながら、バイパス路１７に設けたバイパス流量調整弁１８の開度を制御することで、設定温度の湯として、追焚き回路４０に流し込み、往き管２３と逆止弁４４を有するバイパス流路２６を通じて戻り管１９から両搬送でバスアダプタ２９から浴槽２８内に湯を落とし込む。
【００１６】
次に、このような１缶２水路貯湯方式の風呂給湯装置１における熱量演算方式による残水量判定について説明する。この風呂給湯装置１においては、追焚き回路４０に設けられた浴槽湯温検知センサ２１により浴槽２８から伝熱管８に戻る湯の温度、すなわち浴槽２８内の湯温を検知している。給湯栓１６が閉止状態で風呂単独使用時には、この浴槽湯温検知センサ２１により検知されている浴槽２８内の湯温、即ち風呂温度と、バーナ３から給湯用熱交換器２の水壁内に配された伝熱管８に与えられる熱量、即ち風呂能力との間には例えば図２の（ａ１）に示すような相関関係が存在する。この相関関係は実験的に得ることができる。そこで、浴槽湯温検知センサ２１により測定される風呂温度が、例えば０.５℃変化する毎に風呂能力を測定し、風呂温度と風呂能力との関係をテーブル形式で（あるいは、関数として）コントローラの記憶装置内に記憶させておく。本実験例では関数として次の▲１▼式が得られた。
Ｗ＝−２３０Ｔ＋１５６００ …▲１▼式
ここで、Ｗは標準風呂能力（Ｋｃａｌ／ｈ）、Ｔは風呂温度（℃）を示す。尚、標準風呂能力とは給湯栓１６が閉止状態の風呂単独使用時で、缶体温度が標準温度（ここでは７０℃とする。）のときの風呂能力を指す。
【００１７】
又、給湯栓１６を開放し、給湯栓から出湯すると缶体サーミスタ９で検知される缶体温度が下がる。給湯栓からの出湯量を変化させて（例えば６ｌ／ｍｉｎ、９ｌ／ｍｉｎ）、それぞれの出湯量で風呂温度と風呂能力の関係、及び、風呂温度と缶体温度の関係を測定し、これらをグラフに示すと風呂温度と風呂能力の関係として図２の（ｂ１）、（Ｃ１）の関係が得られ、風呂温度と缶体温度の関係として図２の（ｂ２）、（Ｃ２）の関係が得られた。同様に、（ａ２）は給湯栓１６が閉止状態での風呂温度と缶体温度の関係である。このことは即ち、風呂温度と缶体温度を測定すれば、給湯栓からの出湯量を測定せずとも、又、燃料の消費量を知らずともそのときの風呂能力が分かるということを示している。
【００１８】
これらの測定結果より図３のグラフが導かれ、これを関数に置き換えると▲２▼式が得られた。即ち、
Ｃ＝１−０．０２５（Ｓ−Ｕ） …▲２▼式
ここでＳは標準缶体温度（℃）（例えば７０℃とする。）、Ｕは実測缶体温度（℃）、Ｃは缶体温度が標準温度のときの風呂能力に対する風呂能力の比率、である。
【００１９】
故に、缶体温度に依る補正後の実風呂能力は▲３▼式のように表せる。
Ｐ＝Ｗ×Ｃ …▲３▼式
ここでＰは補正後の実風呂能力（Ｋｃａｌ／ｈ）である。
又、ここでは標準温度を７０℃としたが、７０℃に限定されるものではなく、他の温度（例えば８０℃）であっても構わない。
【００２０】
そして、熱量演算により残水量を求めるための運転を開始するときに浴槽湯温検知センサ２１によって浴槽２８内の湯温、即ち風呂温度Ｔａを計測し、風呂温度Ｔａに対応する標準風呂能力の値Ｗａを▲１▼式により算出し、▲２▼式によりその缶体温度Ｕａでの標準缶体温度時の風呂能力に対する比率Ｃａを算出する。また、▲３▼式により補正後の実風呂能力Ｐａを算出する。同様に熱量演算の運転を終了するときにも浴槽湯温検知センサ２１によって浴槽２８内の湯温、即ち風呂温度Ｔｂを計測し、風呂温度Ｔｂに対応する標準風呂能力の値Ｗｂを▲１▼式により算出し、▲２▼式によりその缶体温度Ｕｂでの標準缶体温度時の風呂能力に対する比率Ｃｂを算出する。また、▲３▼式により補正後の実風呂能力Ｐｂを算出する。ついで、運転開始時の実風呂能力Ｐａ［kcal／hour］と運転終了時の実風呂能力Ｐｂ［kcal／hour］との平均値Ｐmean＝（Ｐａ＋Ｐｂ）／２を用いて熱量演算により残水量を求める。すなわち、熱量演算のための追焚き運転時間がＳ［hour］であるとすると、浴槽２８内の残水量Ｋ［ｌ］は、次の▲４▼式により演算することができる。
Ｋ＝（Ｐmean×Ｓ）／（Ｔｂ−Ｔａ）
＝｛（Ｐｂ＋Ｐａ）×Ｓ｝／２（Ｔｂ−Ｔａ） …▲４▼式
【００２１】
図４は上記のようにして熱量演算で浴槽２８内の残水量を演算し、ついで浴槽２８内の湯を追焚きする手順を具体的に示すフロー図である。この手順に従えば、台所リモートコントローラや浴室リモートコントローラ等に設けられた自動スイッチをオンにすると（Ｓ１）、一定量Ｑ１（例えば、１０リットル）の湯又は水を出湯路１１から湯落とし込み路４１及び追焚き回路４０の往き管２３、戻り管１９を通じて両搬送で浴槽２８内に落とし込む（Ｓ２）。ついで、循環ポンプ２０を運転し、水流スイッチ２２がオンになるか否かによって循環判定を行なう（Ｓ３）。循環判定は、浴槽２８内にバスアダプタレベル以上の残水が存在し、水流スイッチ２２がオンになった場合にはＯＫ（ＹＥＳ）と判定され、浴槽２８内にバスアダプタレベル以下の残水しかなく、水流スイッチ２２がオフの場合にはＯＫでない（ＮＯ）と判定される。
【００２２】
循環判定がＯＫでない場合には、バスアダプタレベル以下の残水しかなく、充分な水量を落とし込んでも浴槽２８から湯が溢れる恐れがないので、一定量の湯Ｑ２（例えば、設定水量−１０リットル）を出湯路１１から湯落とし込み路４１及び追焚き回路４０の往き管２３、戻り管１９を通じて両搬送で浴槽２８内に落とし込む（Ｓ４）。ついで、通常の追焚き運転を行なって浴槽２８内の湯を設定温度まで焚き上げ（Ｓ１２）、例えば４時間の保温運転動作に入る（Ｓ１３）。
【００２３】
これに対し、循環判定がＯＫ（ＹＥＳ）となった場合には、バスアダプタレベル以上の残水が存在し、浴槽２８から溢れないように設定水位くらいまで湯を落とし込みたいので、熱量演算により残水量を求める。熱量演算が開始すると、循環ポンプ２０で浴槽２８内の湯を追焚き回路４０に循環させながらバーナ３で給湯用熱交換器２を加熱することで当該給湯用熱交換器の水壁内の水を加熱して設定温度の、温水とするとともに、水壁内の追焚き回路４０の伝熱管８内を流れる浴槽循環水を間接的に加熱する（Ｓ５）。同時に、熱量演算開始時には、浴槽湯温検知センサ２１により風呂温度Ｔａを、缶体サーミスタ９により缶体温度Ｕａを検知し、コントローラの記憶装置に記憶する（Ｓ６）。一定時間Ｓの追焚き運転が終了すると（Ｓ７）、浴槽湯温検知センサ２１により終了時の風呂温度Ｔｂを、缶体サーミスタ９により終了時の缶体温度Ｕｂを検知し、コントローラの記憶装置に記憶する（Ｓ８）。
【００２４】
こうして熱量演算のための一定時間Ｓの追焚き運転が終了すると、開始時及び終了時の風呂温度Ｔａ、Ｔｂ及び、缶体温度Ｕａ、Ｕｂが記憶装置から読み出され、コントローラにより開始時の風呂温度Ｔａ、缶体温度Ｕａに対応した実風呂能力Ｐａと終了時の風呂温度Ｔｂ、缶体温度Ｕｂに対応した実風呂能力Ｐｂとがテーブルから読み取られ、ついで上記▲４▼式によって残水量Ｋが演算される（Ｓ９）。
【００２５】
残水量Ｋが求まると、コントローラは浴槽２８への注湯が必要かどうか判断し（Ｓ１０）、必要であると判断すれば、設定水量（設定水位までの水量）から残水量Ｋを引いた湯量を浴槽２８に落とし込んだ後（Ｓ１１）、また残水量Ｋが設定水量に近くて注湯が必要ないと判断すれば直ちに、通常の追焚き運転を行なって浴槽２８内の湯を設定温度まで焚き上げ（Ｓ１２）、例えば４時間の保温運転動作に入る（Ｓ１３）。
【００２６】
この実施形態においては、熱量演算のための追焚き運転開始時と終了時に風呂温度と缶体温度を検出し、風呂温度と缶体温度に応じた実風呂能力を用いているので、精度よく残水量を求めることができる。また、この追焚き開始時の実風呂能力と終了時の実風呂能力の平均値を用いているので、簡単な演算により一層残水量の演算精度を高めることができる。
【００２７】
なお、上記実施形態では、開始時と終了時のみに風呂温度と缶体温度を検出したが、一定時間毎に風呂温度と缶体温度を検知し、一定時間毎に変化する実風呂能力を求め、その値を積算して実風呂能力の平均値を求めるようにしてもよい。あるいは、テーブル内に風呂温度と缶体温度の一定温度（例えば、０.５℃）毎の実風呂能力値を有している場合には、一定温度毎の時間間隔を計測し、時間間隔とその時の風呂能力値との積を積算して実風呂能力の平均値を求めるようにしてもよい。
【００２８】
又、上記実施形態では、循環ポンプ２０の循環流量は検知していないが、前もって循環ポンプ２０による循環流量を変化させて、循環流量毎に図２、図３に示されるデータを実験的に求め、テーブル形式で、あるいは関数として何種類か（例えば循環流量８ｌ／ｍｉｎから１ｌ毎に１７ｌ／ｍｉｎまで１０種類）持っておき、追焚き回路４０の往き管２３、又は戻り管１９に循環流量センサを配して循環流量を検知し、その循環流量での実風呂能力を求めるようにしてもよく、この場合、コストの増加を伴うが、残水量を更に精度良く求めることが可能となる。
【００２９】
又、循環流量の検知方法は流量センサによる方法に限らず、簡易的に浴槽湯温検知センサ２１と注水サーミスタ２７との検知温度差から求めても良い。この場合、前もって給湯栓１６閉止で、缶体サーミスタ検知温度安定状態（例えば７０℃）での浴槽湯温検知センサ２１と注水サーミスタ２７との検知温度差と循環流量との関係を実験的に求めておき、テーブル形式で、あるいは関数として持っておく。この方法では流量の検知精度は流量センサによる方法より劣るが、コストの増加を伴うことが無く経済的である。
【図面の簡単な説明】
【図１】本発明の一実施形態による貯湯式１缶２水路方式の風呂給湯装置の構成を示す図である。
【図２】風呂温度と風呂能力、缶体温度との関係を示すグラフである。
【図３】缶体温度差と風呂能力変化率の関係を示すグラフである。
【図４】図１の風呂給湯装置において浴槽内の湯を追焚き処理する手順を示すフロー図である。
【符号の説明】
１風呂給湯装置
２給湯用熱交換器
３バーナ
９缶体サーミスタ
１１出湯路
２０循環ポンプ
２１浴槽湯温検知センサ
２２水流スイッチ
２７注水サーミスタ
２８浴槽
３０給湯路
３１コントローラ
４０追焚き回路
４１湯落とし込み路
５０安全弁
５１空焚き安全装置
５２ストレーナ[0001]
[Technical field to which the invention belongs]
The present invention relates to a bath water heater. More particularly, the present invention relates to a bath water heater of a single-can / two-channel hot water storage system in which a heat transfer tube for replenishing hot water in a bathtub is housed in a water wall of a heat exchanger for hot water supply.
[0002]
[Prior art]
A so-called hot water storage type hot water supply apparatus having a hot water storage unit in a hot water supply apparatus is mainly one of two cans (one burner). In this method, the heat exchange part of the reheating circuit of the bathtub, that is, the heat transfer tube is placed in the water wall of the heat exchanger for hot water supply, and heat exchange for hot water supply is performed with one burner while detecting the temperature of hot water in the water wall. The water in the water wall of the heat exchanger for hot water supply is heated to a preset temperature by heating the water heater, and the circulating water in the bathtub flowing in the heat transfer pipe of the reheating circuit in the water wall is indirectly It is designed to be heated. In addition, in such a hot water storage type, it is common to use a burner with intermittent combustion control with a fixed combustion capacity (combustion heat amount).
[0003]
On the other hand, as a method for detecting the remaining amount of hot water in the bathtub, there is a method called a calorific value calculation method. This method is often used in the two-can two-water channel (two-burner) type, and is a method for detecting the amount of residual water when there is residual water above the bath adapter level in the bathtub. The temperature before the hot water in the bathtub is detected by circulating the hot water in the chasing circuit, and then the hot water in the bath is heated in the chasing circuit for a certain period of time. Detect the rising temperature. Since the combustion capacity (combustion heat amount) of the follow-up circuit is known in advance, the amount of residual water in the bathtub can be thermodynamically calculated from the temperature difference between the soaking temperature and the pre-heating temperature and the combustion time.
[0004]
However, in a hot water storage bath water heater of 1 can / two water channel system, the water in the water wall of the heat exchanger for hot water supply is heated by one burner, and indirectly in the reheating heat transfer pipe in the water wall. Since the circulating hot water in the bathtub is heated, if the hot water in the water wall of the hot water supply heat exchanger is opened and the hot water tap is opened during the reheating for the calorific value calculation, a part of the heat supplied from the burner is obtained. Even if the amount of heat supplied to the circulating hot water in the bathtub, that is, the bath capacity (hereinafter referred to as bath capacity) is reduced and the burner's combustion capacity (combustion heat quantity) is fixed, the rising temperature and the temperature before heating The amount of residual water in the bathtub cannot be calculated thermodynamically from the temperature difference between and the combustion time.
If the amount of heat lost to the hot water supply side, that is, the hot water supply capacity (hereinafter referred to as hot water supply capacity) can be calculated, the bath capacity can be calculated. However, in the case of a hot water storage type, a water amount sensor is generally not provided in the hot water supply circuit. This calculation is not possible.
[0005]
Moreover, in a hot water storage bath water heater of 1 can / two water channel system, even if hot water is not used, if the temperature of the hot water in the bathtub, that is, the temperature of the hot water flowing into the heat transfer pipe for reheating changes, The amount of heat necessary to keep the hot water in the water wall of the heat exchanger at a constant temperature also changes, and the heat exchange efficiency also changes, so the combustion capacity (combustion heat amount) of the burner also changes greatly. (For example, at a hot water temperature of 40 ° C., the combustion capacity is reduced by 50% or more compared to the case of 10 ° C.)
Since no hot water supply is used here, the burner's combustion capacity (combustion heat quantity) indicates the bath capacity.
[0006]
In addition, when a burner with a variable combustion capacity (combustion heat amount) is burned continuously, the amount of heat given by knowing the amount of fuel consumed for a certain period of time can be calculated easily, but the combustion capacity (combustion heat amount) is fixed to the burner. In the case of using the intermittent combustion control type, it is necessary to take a long time to accurately detect the amount of heat given for a certain time, which is not realistic.
Therefore, the residual water amount in the bathtub cannot be calculated thermodynamically from the temperature difference between the rising temperature and the preheating temperature and the combustion time.
Therefore, in order to measure the amount of remaining water in the bathtub, a method is adopted in which a pressure sensor is arranged in the bath adapter, and the amount of remaining water in the bathtub is measured by the output of the pressure sensor for the water level above the bath adapter.
[0007]
However, in the method of placing the pressure sensor on the bath adapter, it is necessary to take out the signal line of the pressure sensor from the bath adapter at the construction site and wire it in the wall, and replacement or repair work at the time of initial construction and due to failure of the pressure sensor It took a lot of man-hours.
[0008]
[Problems to be solved by the invention]
The present invention has been made in order to solve the above technical problems, and the object of the present invention is to provide a one-can / two-channel hot-water storage type hot water supply bath system having a function of calculating a remaining water amount by a calorific value calculation method. The purpose is to be able to accurately calculate the amount of residual water by calculating the amount of heat.
[0009]
[Means for Solving the Problems]
The bath hot water supply apparatus according to claim 1 directly heats the heat exchanger for hot water supply by one burner, and also uses a heat exchanger tube for reheating disposed in the water wall of the heat exchanger as the water heater. In the bath water heater that indirectly heats with hot water in the wall, the hot water in the bathtub is detected by the temperature detecting means for detecting the hot water temperature in the bathtub and the hot water temperature in the water wall. Based on the temperature and the temperature of the hot water in the water wall, the bath capacity used for the remaining water amount calculation by the calorific value calculation method is obtained.
[0010]
Here, the remaining water amount calculation of the calorific value calculation method is to heat the hot water remaining in the bathtub for a predetermined time, and the temperature difference between the hot water temperature before the start of heating and the hot water temperature after the end of heating and the hot water in the bathtub during that time. This is a method for determining the amount of residual water from the given amount of heat. In addition, in order to determine the combustion capacity used for calculating the remaining water amount by the calorific value calculation method according to the hot water temperature in the bathtub, that is, the bath capacity, the relationship between the hot water temperature in the bathtub and the hot water temperature in the water wall of the hot water supply heat exchanger and the bath capacity in advance. Is stored in a storage device or the like.
Here, the hot water temperature in the bathtub may be detected by a temperature sensor arranged in the middle of the circulation circuit of the return hot water temperature of the circulation circuit, or may be detected directly by arranging a temperature sensor in the bath adapter of the bathtub. Any method can be used as long as it can directly or indirectly detect the temperature in the bathtub. In the following description, the bath temperature is referred to as bath temperature.
Further, the detected value of the hot water temperature in the water wall of the hot water supply heat exchanger also varies depending on the detection position, but may be a position where the hot water temperature in the water wall can be detected directly or indirectly. In the following description, this hot water temperature in the water wall is referred to as a can body temperature.
[0011]
In the bath water heater of the present invention, since the bath capacity used for the remaining water amount calculation is obtained according to the bath temperature and the can body temperature, it is corrected according to the bath temperature and the can body temperature. The value of the bath capacity can be used, and even in the case of using a one-can / two-channel hot water bath hot water supply system with intermittent combustion control with a fixed combustion capacity (combustion calorie) for the burner, The amount of residual water can be calculated accurately.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic configuration diagram showing a bath water heater 1 of a single can / two-channel hot water storage system according to an embodiment of the present invention. This bath hot water supply apparatus 1 is an oil type that uses oil as fuel, and a burner 3 for combusting oil is provided at the lower part of a heat exchanger 2 for hot water supply, and oil is supplied from an oil supply pipe 4 by an oil pump 5. Is supplied, and intermittent combustion control is performed with the combustion capacity (combustion heat quantity) fixed to maintain the can body temperature detected by the can body thermistor 9 at the set temperature.
In addition, a blower 6 for forcibly sending combustion air is provided at the upper part of the burner 3, and air or exhaust gas forcedly blown from the blower 6 is discharged from the exhaust tube 7 to the outside. Further, in the water wall of the hot water supply heat exchanger 2, a heat transfer tube 8, which is a reheating heat exchanging portion of the reheating circuit 40 connected to the bus adapter 29 of the bathtub 28, is disposed.
[0013]
The hot water supply path 30 includes a water inlet path 10 connected to the water inlet side of the heat exchanger 2 for hot water supply and a hot water outlet path 11 connected to the hot water outlet side. The water inlet path 10 includes a check valve 12 and a safety valve 13. Is provided. Thus, when the hot water tap 16 provided at the pipe end of the hot water outlet 11 is opened, the water flowing through the hot water outlet 30 is heated by the hot water heat exchanger 2 heated by the burner 3, and as hot water having a set temperature. The hot water is discharged from the hot water tap 16.
[0014]
The reheating circuit 40 includes a heat transfer tube 8 which is a heat exchanger for reheating, a return pipe 19 connected to the heat transfer pipe 8, and an outgoing pipe 23. The return pipe 19 includes a circulation pump 20, a bath water temperature detection sensor 21, A water flow switch 22 is provided. Thus, when replenishing the hot water in the bathtub 28, it is confirmed that there is hot water of a level higher than the bus adapter level by operating the circulation pump 20, and then the hot water supply heat heated by the burner 3 is confirmed. The hot water circulating in the reheating circuit 40 is heated by the heat transfer pipe 8 arranged in the water wall of the exchanger 2, and the temperature of the hot water in the bathtub 28 detected by the bathtub hot water temperature detection sensor 21 reaches the set temperature. Then, the operation of the circulation pump 20 is stopped.
[0015]
A hot water drop passage 41 branched from the pipe end portion of the hot water discharge passage 11 is connected to the water intake passage 10 and the bypass passage 17 provided with the bypass flow rate adjusting valve 18 via an orifice 46, and the drop opening / closing valve 24 and It is connected in the middle of the forward pipe 23 of the follow-up circuit 40 via the pouring water amount sensor 25 and the check valves 42, 43, and is a bypass provided with a check valve 44 between the forward pipe 23 and the return pipe 19. A flow path 26 is provided. Thus, when hot water is dropped into the bathtub 28 and filled with the hot water in the bathtub 28, the dropping on-off valve 24 is opened, heated by the hot water supply heat exchanger 2 in the hot water supply path 30, and hot water flowing out from the hot water supply path 11. By controlling the opening of the bypass flow rate adjusting valve 18 provided in the bypass passage 17 while regulating the flow rate with the orifice 46 and detecting the temperature with the water injection thermistor 27 disposed in the forward pipe 23 of the tracking circuit 40, As hot water having a set temperature, the hot water is poured into the follow-up circuit 40, and the hot water is dropped into the bathtub 28 from the bus adapter 29 through the bypass pipe 26 having the forward pipe 23 and the check valve 44.
[0016]
Next, the remaining water amount determination by the calorific value calculation method in the bath water heater 1 of such a single can / two water channel hot water storage method will be described. In this bath hot water supply apparatus 1, the temperature of hot water returning from the bathtub 28 to the heat transfer tube 8, that is, the temperature of hot water in the bathtub 28 is detected by the bathtub hot water temperature detection sensor 21 provided in the tracking circuit 40. When the hot-water tap 16 is closed and the bath is used alone, the hot water temperature in the bathtub 28 detected by the bathtub hot water temperature detection sensor 21, that is, the bath temperature, and the water wall of the heat exchanger 2 for hot water supply from the burner 3. There is a correlation as shown in (a1) of FIG. 2 between the amount of heat given to the arranged heat transfer tubes 8, that is, the bath capacity. This correlation can be obtained experimentally. Therefore, every time the bath temperature measured by the bath water temperature detection sensor 21 changes by 0.5 ° C., for example, the bath capacity is measured, and the relationship between the bath temperature and the bath capacity is expressed in a table format (or as a function) as a controller. This is stored in the storage device. In this experimental example, the following equation (1) was obtained as a function.
W = −230T + 15600 (1) where W is the standard bath capacity (Kcal / h) and T is the bath temperature (° C.). The standard bath capacity refers to the bath capacity when the can body temperature is the standard temperature (70 ° C. in this case) when using the bath alone with the hot-water tap 16 closed.
[0017]
Moreover, when the hot-water tap 16 is opened and the hot water is discharged from the hot-water tap, the can body temperature detected by the can body thermistor 9 is lowered. Change the amount of hot water discharged from the hot water tap (for example, 6 l / min, 9 l / min), and measure the relationship between the bath temperature and the bath capacity and the relationship between the bath temperature and the can body temperature at each amount of hot water. When the graph shows, the relationship between (b1) and (C1) in FIG. 2 is obtained as the relationship between the bath temperature and the bath capacity, and the relationship between (b2) and (C2) in FIG. 2 as the relationship between the bath temperature and the can body temperature. Obtained. Similarly, (a2) is the relationship between the bath temperature and the can body temperature when the hot-water tap 16 is closed. This means that if the bath temperature and can temperature are measured, the bath capacity at that time can be understood without measuring the amount of hot water discharged from the hot water tap or without knowing the amount of fuel consumed. .
[0018]
The graph of FIG. 3 was derived from these measurement results, and when this was replaced with a function, equation (2) was obtained. That is,
C = 1−0.025 (S−U) (2) Formula where S is a standard can body temperature (° C.) (for example, 70 ° C.), U is a measured can body temperature (° C.), and C is a can. The ratio of the bath capacity to the bath capacity when the body temperature is the standard temperature.
[0019]
Therefore, the actual bath capacity after correction depending on the can body temperature can be expressed by the equation (3).
P = W × C (3) where P is the corrected actual bath capacity (Kcal / h).
Although the standard temperature is 70 ° C. here, the temperature is not limited to 70 ° C., and may be another temperature (for example, 80 ° C.).
[0020]
When the operation for determining the amount of remaining water is started by calculating the amount of heat, the bath water temperature detection sensor 21 measures the hot water temperature in the bath 28, that is, the bath temperature Ta, and the value of the standard bath capacity corresponding to the bath temperature Ta. Wa is calculated by the equation (1), and the ratio Ca to the bath capacity at the standard can body temperature at the can body temperature Ua is calculated by the equation (2). Further, the corrected actual bath capacity Pa is calculated by the equation (3). Similarly, when the operation of the calorific value is finished, the hot water temperature in the bathtub 28, that is, the bath temperature Tb is measured by the bath water temperature detection sensor 21, and the standard bath capacity value Wb corresponding to the bath temperature Tb is set to (1). The ratio Cb to the bath capacity at the standard can body temperature at the can body temperature Ub is calculated from the expression (2). Further, the corrected actual bath capacity Pb is calculated by the equation (3). Next, the remaining water amount is obtained by calorific value calculation using the average value Pmean = (Pa + Pb) / 2 between the actual bath capacity Pa [kcal / hour] at the start of operation and the actual bath capacity Pb [kcal / hour] at the end of operation. . That is, if the reheating operation time for calculating the amount of heat is S [hour], the remaining water amount K [l] in the bathtub 28 can be calculated by the following equation (4).
K = (Pmean × S) / (Tb−Ta)
= {(Pb + Pa) × S} / 2 (Tb−Ta) (4) Formula
FIG. 4 is a flowchart specifically showing the procedure for calculating the amount of remaining water in the bathtub 28 by calorie calculation as described above and then pursuing hot water in the bathtub 28. According to this procedure, when an automatic switch provided in a kitchen remote controller, a bathroom remote controller or the like is turned on (S1), a fixed amount Q1 (for example, 10 liters) of hot water or water is poured from the hot water outlet 11 into the hot water dropping path 41. And it drops into the bathtub 28 by both conveyances through the forward pipe 23 and the return pipe 19 of the tracking circuit 40 (S2). Next, the circulation pump 20 is operated, and the circulation determination is performed based on whether or not the water flow switch 22 is turned on (S3). In the circulation determination, when there is residual water at the bath adapter level or higher in the bathtub 28 and the water flow switch 22 is turned on, it is determined as OK (YES), and only residual water at the bus adapter level or lower in the bathtub 28 is determined. If the water flow switch 22 is off, it is determined that it is not OK (NO).
[0022]
If the circulation determination is not OK, there is only residual water below the bath adapter level, and even if a sufficient amount of water is dropped, there is no risk of hot water overflowing from the bathtub 28, so a certain amount of hot water Q2 (for example, set water volume -10 liters) Is dropped into the bathtub 28 by both transports through the hot water dropping path 41 and the forward pipe 23 and return pipe 19 of the chase circuit 40 (S4). Next, a normal reheating operation is performed to raise the hot water in the bathtub 28 to a set temperature (S12), and, for example, a 4-hour heat retention operation is started (S13).
[0023]
On the other hand, if the circulation judgment is OK (YES), there is residual water above the bus adapter level and it is desired to drop the hot water to the set water level so as not to overflow from the bathtub 28. Find the amount of water. When the calorific value calculation starts, the hot water in the bathtub 28 is circulated through the recirculation circuit 40 by the circulation pump 20 and the hot water supply heat exchanger 2 is heated by the burner 3, whereby the water in the water wall of the hot water supply heat exchanger is heated. Is heated to a preset temperature of hot water, and the circulating water in the bathtub flowing in the heat transfer pipe 8 of the reheating circuit 40 in the water wall is indirectly heated (S5). At the same time, when the calorific value calculation is started, the bath temperature Ta is detected by the bath water temperature detection sensor 21 and the can body temperature Ua is detected by the can body thermistor 9 and stored in the storage device of the controller (S6). When the chasing operation for a predetermined time S is finished (S7), the bath temperature Tb at the end is detected by the bath water temperature detection sensor 21, and the can temperature Ub at the end is detected by the can body thermistor 9, and is stored in the storage device of the controller. Store (S8).
[0024]
When the chasing operation for a certain time S for calculating the amount of heat is thus completed, the bath temperatures Ta and Tb at the start and at the end and the can body temperatures Ua and Ub are read from the storage device, and the bath at the start is started by the controller. The actual bath capacity Pa corresponding to the temperature Ta and the can body temperature Ua, the bath temperature Tb at the end time, and the actual bath capacity Pb corresponding to the can body temperature Ub are read from the table. Is calculated (S9).
[0025]
When the remaining water amount K is obtained, the controller determines whether or not it is necessary to pour water into the bathtub 28 (S10), and if it is determined that it is necessary, the amount of hot water obtained by subtracting the remaining water amount K from the set water amount (water amount up to the set water level). Is dropped into the bathtub 28 (S11), and if it is determined that the remaining water amount K is close to the set water amount and no pouring is required, the ordinary reheating operation is performed to bring the hot water in the bathtub 28 to the set temperature. Increase (S12), for example, a heat insulation operation for 4 hours is started (S13).
[0026]
In this embodiment, the bath temperature and can body temperature are detected at the start and end of the chasing operation for the calorific value calculation, and the actual bath capacity corresponding to the bath temperature and can body temperature is used. The amount of water can be determined. In addition, since the average value of the actual bath capacity at the start of chasing and the actual bath capacity at the end of the chasing is used, the calculation accuracy of the remaining water amount can be further increased by a simple calculation.
[0027]
In the above embodiment, the bath temperature and the can body temperature are detected only at the start time and at the end time. However, the bath temperature and the can body temperature are detected at regular intervals, and the actual bath capacity that changes at regular intervals is obtained. The average value of the actual bath capacity may be obtained by integrating the values. Alternatively, if the table has an actual bath capacity value for each constant temperature (for example, 0.5 ° C.) of bath temperature and can body temperature, measure the time interval for each constant temperature, The average value of the actual bath capacity may be obtained by integrating the product with the bath capacity value at that time.
[0028]
In the above embodiment, the circulation flow rate of the circulation pump 20 is not detected. However, the circulation flow rate of the circulation pump 20 is changed in advance, and the data shown in FIGS. 2 and 3 are experimentally obtained for each circulation flow rate. In the form of a table or as a function, several types (for example, 10 types of circulating flow rate from 8 l / min to 17 l / min per l) are held, and the circulating flow rate sensor is connected to the forward pipe 23 or the return pipe 19 of the tracking circuit 40. It is also possible to detect the circulating flow rate and obtain the actual bath capacity at the circulating flow rate. In this case, although the cost increases, the remaining water amount can be obtained more accurately.
[0029]
Further, the method for detecting the circulating flow rate is not limited to the method using the flow rate sensor, but may be simply obtained from the detected temperature difference between the bath water temperature detection sensor 21 and the water injection thermistor 27. In this case, the relationship between the detected temperature difference between the bath water temperature detection sensor 21 and the water injection thermistor 27 and the circulating flow rate in a stable state of the can body thermistor detection temperature (for example, 70 ° C.) is experimentally obtained by previously closing the hot water tap 16. Keep it in table format or as a function. In this method, the detection accuracy of the flow rate is inferior to the method using the flow rate sensor, but it is economical without increasing the cost.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a hot water storage type 1 can / two water channel bath hot water supply apparatus according to an embodiment of the present invention.
FIG. 2 is a graph showing the relationship between bath temperature, bath capacity, and can body temperature.
FIG. 3 is a graph showing the relationship between can body temperature difference and bath capacity change rate.
4 is a flowchart showing a procedure for replenishing hot water in a bathtub in the hot water supply apparatus of FIG. 1. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Bath hot water supply apparatus 2 Heat exchanger 3 for hot water supply Burner 9 Can body thermistor 11 Hot water supply path 20 Circulation pump 21 Bathtub hot water temperature detection sensor 22 Water flow switch 27 Water injection thermistor 28 Bathtub 30 Hot water supply path 31 Controller 40 Reheating circuit 41 Hot water dropping path 50 Safety valve 51 Air-fired safety device 52 Strainer

Claims

１箇所のバーナによって給湯用の熱交換器を直接加熱し、又、当該熱交換器の水壁内に配された追焚き用の伝熱管を当該水壁内の温水で間接的に加熱する風呂給湯装置において、浴槽内の湯温と当該水壁内温水温度を検出するための温度検知手段を備え、当該温度検知手段によって検知された浴槽内の湯温と当該水壁内温水温度に基づき、熱量演算方式による残水量演算に用いる風呂能力を求めるようにしたことを特徴とする風呂給湯装置。A hot water supply heat exchanger is directly heated by a single burner, and a reheating heat transfer tube arranged in the water wall of the heat exchanger is indirectly heated with hot water in the water wall. In the hot water supply apparatus, it is provided with temperature detection means for detecting the hot water temperature in the bathtub and the temperature of the hot water in the water wall, and based on the hot water temperature in the bathtub and the hot water temperature in the water wall detected by the temperature detection means, A bath hot water supply apparatus characterized by obtaining a bath capacity used for calculating a remaining water amount by a calorie calculation method.